Design And Research On Vibration Measurement System Of Ship Shafting

Nowadays, with the people pay more and more attention to the vibration of ship shafting, it becomes more important to get a further research. There are lots of theoretical researches about the vibration of ship shafting at home and abroad, but because of complexity of shafting and variability of environment during work, the calculation formulas of theoretic are proximity and narrow limitation, which can’t reflect the real vibration. So it is necessary to design a measurement system of shafting vibration, which has high accuracy and high credibility. The paper together with the technology of test, transducer, developing of SCM and analysis of signal, and then develop a new measurement system of shafting vibration, which based on traditional electrometric method. The system has the features of high accuracy, width frequency range, stabilize performance, simple structure, etc.The hardware design of measurement system include acquisition of signal and pretreatment, circuit switching of A/D, CPU, RAM and flash RAM, circuit of LCD, interior electrical source, USB and rotate mouse. The main function of those modules are achieve collecting of vibration signal, pretreatment, A/D conversion, retreatment, display, storage, export of data and so on. In which, the reasonable design of the acquisition of signal and pretreatment is foundation and guarantee to improve accuracy and reliability of the whole system. The principle of design is improving the anti-interference of element as far as possible, so the signal which takes along the vibration can far away from the affect of ambience.The software of measurement system includes both lower computer software and upper computer (PC) software. The former uses UltraEdit text editor to programming all CMOS chips in order to achieve the function of parameter setting, distortion point treatment, display of time domain waveform, etc. And the latter uses the programming language of C#to carry out the function of average treatment, FFT, display of time and frequency domain waveform, export of frequency domain data and so on. The principle of software design is friendly interface, fast treatment of data, high accuracy of FFT, easy to maintenance and promotion, etc.During the developing of measurement system, use the prescaler to inspect the function of acquisition of signal, transmission, analysis and treatment of signal, etc. And when the system is completed, took the test of torsion vibration and transverse vibration with the combined propulsion plant test-bed of two diesels and electric plant. Comparison with the result of theoretical arithmetic and the measurement data of ZDCL-Ⅳ, we can know that the new measurement system is satisfied. In addition, via analysis the data of torsion vibration test, research some of factors which affect the accuracy of it, such as rolling vibration and number of divisions. And then come up with some effect methods which can avoid error of test.